题目内容：

定语从句,问题
This is the place where we first met with each other
Library is a place which / where we must keep quiet
这两句,where 如果用 which 替换,是 in which ,吗? 这里可以是at which 么?
2 关系副词如 where 也是代替它前面的 先行词,在句中担任成分吧? 是状语?谢谢.